The present invention relates to prosthodontics, and in particular to a method for facilitating dental restorations, such as the construction of complete dentures.
The accurate determination of the vertical jaw relation is extremely important in the fitting of dentures, as well as in other dental restoration work. Vertical relation, or vertical dimension refers to the degree of separation between the mandible, or lower jaw-bone and the maxillae, or upper jaw-bone. An appreciable increase or decrease in the vertical dimension of the mandible to the maxillae may cause problems in masticatory performance and speech. Deviations in vertical dimension may also cause temporomandibular joint disorders, which are often accompanied by severe physical discomfort in the jaw and neck regions. In certain cases, soreness of the supporting tissues may result, making the jaw region a target for rapid bone resorption.
In practice, the determination of the occlusal vertical dimension is the starting point for complete denture treatment. Occlusal vertical dimension is generally defined as the vertical dimension of the face when the teeth are in natural maximum contact in centric occlusion, i.e., with the posterior teeth fitting tightly together. Determination of the occlusal vertical dimension establishes the reference position from which all other horizontal jaw relation positions are recorded.
Many techniques have been proposed heretofore for facilitating the determination of occusal vertical dimension. Preextraction records, such as profile photographs, softwire profile silhouettes, occluded diagnostic casts, resin face masks and facial measurements have been found to be of value in many cases. Various instruments have been used for making facial measurements, including Sorenson's profile guide and the Willis device. More sophisticated approaches, such as radiographic techniques and electromyography have also been used. The Boos Bimeter, a device that measures the maximum force of jaw closure has been advocated by some clinicians and researchers. In addition, the patient's swallowing threshold, closest speaking space, phonetics, tactile sense, and parallelism of the ridges in the posterior region of the jaw have been used with varying degrees of success.
Although there are a number of different approaches in use, it is generally acknowledged by experienced prosthodontists that there is no precise scientific method of determining the correct occlusal vertical dimension. The acceptability of any vertical dimension determination depends largely upon the skill, experience and judgment of the prosthodontist. Thus, a need exists for a reliable method for accurately determining vertical dimension to facilitate dental restorations.